<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      const arr = [
        { id: '29', pid: '', name: '总裁办' },
        { id: '2c', pid: '', name: '财务部' },
        { id: '2d', pid: '2c', name: '财务核算部' },
        { id: '2f', pid: '2c', name: '薪资管理部' },
        { id: 'd2', pid: '', name: '技术部' },
        { id: 'd3', pid: 'd2', name: 'Java研发部' },
        { id: 'd31', pid: '2f', name: 'Java研发部111' },
      ];

      // 使用递归来实现 平铺结构 转树形
      // 两个参数  要转会的数组arr  第二个参数，就是要转换的父id
      function transformListToTree(arr, pid) {
        function recursion(pid) {
          const res = [];
          arr.forEach((item) => {
            if (item.pid === pid) {
              res.push(item);
              item.children = recursion(item.id);
            }
          });
          return res;
        }

        return recursion(pid);
      }

      const newArr = transformListToTree(arr, '');
      console.log(newArr);
    </script>
  </body>
</html>
